Thief-hole cover for liquid containers



J. H, WIGGINS THLEF HOLE covmron LIQUID CQNTAINERS Ftlid Hay. 21, 192:52 Sheets-Sheet l sept. 22, 1925.

Sept. 22, 1925.

- J. H. wlGGlNs THIEF HOIJE COVER FOR LIQUID CONTAINERS mea uw 21, 192sf 2 sheets-snaai 2 IN VEN TOR N m wr T #um J, Vl B instrument todetermine the depth or ap-' proximate quantity of the oil in the tank.

Patented Sept. 22, 1925.

' UNITED STATES JOHN n. WIGGINS, `OF BARTLESVILLE OKLAHOMA.

TIIIEF-HOLE COVER FOR LIQUID CONTAINERS. -l

Application led May 21, 1923. Serial No.\640,628.

To all whom t may concem Be it knownthat I, JOHN H. WIGGINs, a

citizen of the yUnited States, residing at Bar- .h tlesville, Oklahoma,have invented a certain.

new and useful Improvement in Thief-Hole Covers for Liquid Containers,of which the following is a'full, clear, andeXact description, such aswill enable others skilled in the art to which it appertains to make'anduse the same. -v

This invention relates tofdevices of the kind that are knowncommercially'as thief hole covers, namely, closures such as are used onoil storage tanks for coveringthe vgauging hole in the roof or top ofthe tank through which a gauger inserts a measuring One object of mypresent invention is to provide a thief hole cover, which, in additionto effectively sealing the contents of the tank from the atmosphere,also serves as a differential pressure regulator that will automaticallyrelieve an abnormal internal presi sure in the container on which it isused andpermit air to enter the container during the operation ofwithdrawing liquid from same.

Another object is to provide a vthief hole cover of the general kindreferred to which is so constructed that it can be opened and retainedin its open position by pressure applied to same by the gaugers foot,and when said pressure is relieved, will close automaticallyand remainin such condition that it seryes as a differential pressure regulatorfor the container.

.Another `Objectis to provide a' combined differential pressureregulator and liquid sealed thief hole cover which is'so constructedthat gases can escape from the interior` of the container, in the `eventof an abnormal internal pressure, and air can enterv the containerduring the operation Of withdrawing liquid therefrom without liabilityof destroying the liquid seal or liquid seal inoperative.

And still another object is to .provide a liquid sealed thief hole coverwhich is so constructed that the sealing liquid which drips off the lidOr movable element of the cover"when vit is moved into its openposition' will be collected and conducted back into the reservoir whichholds the sealing liquid. Other Objects and desirable features ofluy-invention will be hereinafter pointed out.

rendering the Figure 1 ofthe drawings is a vertical cross-sectional viewOf a combined thief constructed in accordance with my invention. t

.Figure 2 is a top plan view of the stationary member ofthe device thatcontains ole cover and differential pressure regulator the reservoir forthe sealing liquid; andy l Figure 3 is a bottom plan View ofthe lid ormovable element of the device. 4

My improved thief hole cover consists of a stationaryV member A adaptedto be connected to the roof or top 1 of the liquid voon'- tainer at apoint in alignment with a hole or -opening in said roof 1 and ka movablemember or lid B that is normally arrangedover the membenA, as shown inFigure l, 'The member A is of circular form in general outline and isreservoir 2 that 1s adapted to contain a sealing liquid w which receivesan annular sealing device 3 on the underside of the lid B,

rovided with an annular i thus producing a liquid seal that effectivelycuts Ofi' the contents of'the container from.`

the atmosphere. The lid B is of slightly greater diameter than themember A and is hinged to said member by a pintle pin 4 that passesthrough a depending 'hingemember 5 on the lid that is embraced by iapairof laterally-projecting ears 6 on the member A.

In order lthat the device will erform the' dual function of a liquid seale thief hole coverl and differential pressure regulator, I constructthe members A and B in such a` mannerthat gases can break through theliquid seal in case an abnormal internal presysure is crea ed 1n thecontalner, thus automatically rel eving the internal pressure, and aircan break through said liquid seal andenter the container when liquid isbeing withdrawn from the container, thereby automatically relieving thevacuum that is created in the` container during the operation ofwithdrawing liquid-from same. In the form of ymy inventionhereinillustrated'this 1s effected by designing the members A and `B .insuch a way that spaces or passagewaysy are provided between the member Band the upper portion of the member A and between the lower edge of thesealing device 3 and the bottom-of the liquid reservoir`2 when the. lidor movable member B is in its closed positioni, as shown in. Ifigure 1.One convenient way of mamtaining the members A and B in approximatelythe relative position tions von which the underside o 20 rests when saidlid is in its closed positlon.

. The' liquid -reservoir 2 is preferablyl sub- 3, that bearl upon thebottom of the lliquid reservoir 2, thereby holding the major portion ofthe bottom edge ofthe sealing device 3 spaced awayr from the bottom of4the liquid reservoir 2 inthe' member A and maintaining the underside ofthe membenB spaced slightly away from the top edge of .the member A.Obviously, the same result could be obtained by forming spaced lugsv orprojections. on the bottom of the liquid reservoir on which the sealingdevice 3 of the lid-B rests when said lid isv in its closed p0- sition,or by providing the -upper edge of the member A with spaced lugs orprojeci" the 11a B.

stantially wedge-.shaped in vertical cross section, or is of greaterwidth at its upper end than at its llower end so as-to prevent thesealing liquid from being displaced from or carried out of the liquidreservoir 2 by gases escaping from the container lor by air l which isdrawn into the container during the operation of withdrawing liquid fromthe container. I also prefer to make' the outer wall of. the liquidreservoir 2 deeper or slightly higher than the inner wall 'of saidreservoir and provide said inner wall with overflow holes 7, as shown inFi ure 1. If

, an abnormal pressure is created 1n the con-v tainer. due to aninternal explosion or to the accumulation .of-a large quantity of gases,

i said pressure will be exerted on the portion of the sealing liquidlying between the inner wallof the liquid reservoir 2 and the inner sideof the sealing device 3, thus causing the sealing liquid to rise in thespace between the outer wall of the liquid reservoir 2 and the outerside of the sealing device 3.

Owing tothe fact that this space increases gradually in width or Sareafrom its lower towards its upper end, there is little liabilityv ofthesealingliquid vbeing discharged. from,

.the reservoir 2 with the escaping gases, be-

5l) cause the escaping gases will break through-A the 'liquid beforetheliquid has risen-to theupper `edge .of the 'outer wall of the liquidreservoir2. In other words, if the internal 3 and theinner wall of thereservoir 2 one inch, the liquid lying between the sealing de.-

vice 3 and the outer wall ofthe liquid reser- -voir willriseconsiderably less than one inch,

160 due to the fact 'that the space between said outer wall and sealingdevice increases from its lower towards its upper end. When the -'liquidis being withdrawn from the con-- f tainer the vacuum that is created inthe container 4is exerted on the portion of the sealing liquid lyingbetween the sealing device 3 and the inner wall of the liquid reser-Voir 2 in such a way that the liquid in'this space will rise and theliquid in the space between the sealing device 3 and the outer wall oithe liquid reservoir will drop. The liquid in the -space between theinner wall of the reservoir 2 `and the sealing device 3 rises upwardlyuntil it reaches the overfiow holes 7 in said inner wall, whereupon someof the liquid will pass into the container through said overflow holes,the space above Said overflow holes then functioning as a separatingspace for bubbles of air entering the container, and thus preventing toomuch. or' the liquid from splashing out of said reservoir into thecontainer. When the operation of withdrawing' liquid from the tankceases, the sealing -liquid in the space between the sealing device 3and the inner wall of the reservoir 2 drops downwardly and the liquid inthe space between said sealing device and the outer wall of thereservoir 2 rises, thus causing the sSealing device 3 to be submerged ina body of .liquid thatieectively seals the container. wWhen liquid isbeing introduced into the container, the sealing liquid inthe spacebetween the .sealing device 3 and the outer wall of the reservoir 2rises, but on account of the V-shape, crosssectional form of'saidreservoir the sealing liquid' will not rise high enough to splash out ofs-iid reservoirvonto thetop 1 ofthe container; While some of the sealingliquid escapes fronithe reservoir 2 into 'the con tainer, asabove'described, duringthe operaltion of withdrawing liquid from thecon-4 tainer, thls is not objectionable,because the -ga`ugerwillreplenish the sealing liquid in the reservoir 2 whenever he sees that itcontains less than the required quantity of sealing liquid by emptyinghis gaugingdevice into said reservoir, thus insuring that the reservoir2 will always contain an adequate supply of fresh sealing liquid,usually oil, which is. no t sticky -or gummy enough to prevent "it fromfunctioning properly to admit air to the container during' the operationof withdrawing liquid from same and torelieve the pressure in thecontainer .during the. operation of filling the same.

To facilitate the opening and closing of the lid or 4movable member B oftheldevice pressure in the container is suliqcient to dis'- I prefer toprovide said lid with a foot piece` 55 place the liquid between .thesealing device` 8 arranged 'adjacent the hinge between said lid and themember, A land equipped with an angularlyfdisposed, upturned portion 8aon which the gauger can-place his foot and exert downwardpressure, so asto swing the lid upwardly to withdraw the sealing device `3 from theliquid reservoir 2 and 'unc'overthe opening. in the roof 1 of thecontainer which the stationary member A of the device surrounds.Preferably, the foot piece 8 is so'vproportioned and designed that yusdicated bybroken lines in Figure 1, the lid vB will be fully open. Whenthe gauger removes his foot from the angularly-disposed ravity'ycausessaid lid to swing downwardly intoits closed position, thus causing thecontents of the container to be cut oli from the nectin atmosphere, butin'sucha way'that air'can en r the container to relieve the vacuum whenliquidi is' 'being'withdrawn from. the container, vand gases can, escapefrom the container, in the event an`abnormal pressure is created in the,container. The particular styl'e or type of hinge. that is used forconthe lid B to the member A is immatrlal, but I prefer to form thehinge member' on the foot. piece 8 on the4 lid B,

- liquid `I provide. the stationary member A of the device with alaterally-.projecting porso as to reducel the cost and simplify theconstruction of the device and enable the lidto be formed from a'casting offsimple de'si I also prefer to' provide the lid B' with a e-`pending ange 9 at its peripheral edge that projects downwardly slightlybelow the top -edge ofthe outer wall of the liquid reservoir 2, butwhich is spaced .slightly away from said wall, as shown in Figure 1,when thelid of the devicel is in its closed position, said flangeoperating to prevent rain from get`.

' ting into the sealing-reservoir 2.

When the lidB is swung upwardly into its open position some of thesealing liquid .adheres to the sealing device 3 on-said lid. In order tocollect and recover this adhering tionV 10 arranged on the outer wall ofthe liquid reservoir 2 at a point above the hinge lugs or ears 6 onthemember' A, :so that it 'will forma cup which receives liquid that' dri soi the sealing device 3 of the lid when sai' lid is in its raisedposition, said lid also being provided with a. laterally-projectingportion 10, as shown in Figure 3, that extends over said drip'cup10,theliquid 4that back into thevliquid reservoir 2.

collects in the cup 10 draining out ofsame A thief hole cover of the.construction above described leffectively seals thecontents ofthe liquidcontainer on which it isused from the atmosphere, and it serv'es as adifferential pressure regulator to automatically.- -relieve a vacuum orvan abnormal pressurey in the container. Consequently, 1t overco'mes thenecessity of equipping an oil storage tank with two'separate devices, ashas heretofore been the usual practice, namely,`

' with a thief -hole cover and an automatlc `-vent device; it is of suchdesign ,that the lid 'of -sarne can be swung into its open -position-and retained in its open position by the foot of the gauger, and `whenthe gaugers 'Y foot is' removed from the foot piece 8 of the cover, saidcover will return automatically a device is inexpensive to manufactureand itis easy to install, as it is only .composed of-two'partsof simplede esign,` one of'which 70 portion 8n of the foot piecedn the l1d,B,

ervoir at a point above the` hinge of said lid for receivingliquidthat-drips'of said 85 lid when the lid is in its raised position.

2. A combined thief hole cover and dii'erential pressure regulator forliquid containers, comprising a stationary member ada t'- ed to beconnected tothe top or roof *o a'90 container and provided with anannular reservoir that is adapted to contain' a sealing liquid, hin eears on said memberjthat project. latera ly from "the outer wall of saidreservoir, a lid pivotally connected tov said 96 hinge ears and providedwith an annular `sealing'device that'` projects downinto said reservoir,spaced lugslon the lower edge of said sealing device that rest on thbottom of said reservoir when saidlid is closed, Aa ,100

foot 'piece 011 said lid having-an upturned portion on which the userexerts pressure with his yfoot to swing thelid'into its open position,and a drip cup on said stationary member projecting laterally fromsaidres- 106 ervoir at a point above said hinge ears' for receiving andcollecting'liquid that drips of the lid when thelid is raised. 3. Acombined thief holepcover and dit? `ferential pressureregulatorfor'liquid con- 110 tainers, comprising a stationary membervadapted to be connected to the vtop or roof Iaf a container andprovided with an annular reservoirthat is adapted to contain a sealingliquid, hinge ears on said member that project laterally from the -outerwall of said reservoir, a lid pivotally connected to said hinge ears,and provided with an annular sealing'devlce that projects down intosaid reservoir, spaced lugs on the lower edge of said sealing ldevicethatrest on the bttom of said reservoir when said lidl is closed, aJfoot piece on said lid having an upturned portion on which theuser-exerts pressure with his foot to swing the lid into its open lbeing of substantially wedge shape in vertical cross section andprovided with an outer wall of greater height or depth than. its innerwall, overflow Vholes in the inner Wall of said reservoir, and adepending flange on lsaid lid that projects downwardly below the top'.edge of the outer wall of said reservoir.

Il. A combined thief hole cover and pressure regulator for liquidcontainers, comprising a stationary member adapted to be connected tothe top or roof of a container and provided with a reservoir that,isadapted to hold a sealing liquid, said reservoir' being substantiallywedge-shaped in cross section and having the top edge of its outer` Wallterminating ata higher point than the top edge of its inner wall, amovable lid,

- and a sealing device on said lid projecting downwardly into saidreservoir and having spaces or passageii-'ays'between its lower edge andthe bottom of the reservoir, said i, through the l passagewaybetweensaid seala Y 1,554,779.A

ing'device and the inner Wall of said (reservolr,

5. A 'combined thief hole cover and pres.

sure regulator for liquid containers, comprising a stationary'memberadapted to be connected to the topor roof of a container and providedwith a reservoir that is' adapted to hold a' sealing liquid, saidreservoir beingl substantially Wedge-shaped in cross section and havingthe top edge ofA itsouter wall -terminating at a higher -point than theto edge of its inner wall, overflow holes in sai inner wall adjacent thetop edge o f same, a

movable lid, and a sealing device on-said lid projecting downwardly intosaid reser-v voir and having spaces or passageways'between its loweredge and the bottom of the reservoir, said sealing device being spacedaway from the inner and outer walls of said reservoir andV the top edgeof the inner wall of said reservoir being. spaced away from theunderside of the lid so as to permit air or gases to enter or escapefrom the con-A tainer through the passageway between said sealing deviceandthe inner wall of said reservoir.

JOHN HQWIGGINS. I

